1 #define _BSD_SOURCE
2 #include <string.h>
3 #include <stdint.h>
4 #include <limits.h>
5
6 #define ALIGN (sizeof(size_t)-1)
7 #define ONES ((size_t)-1/UCHAR_MAX)
8 #define HIGHS (ONES * (UCHAR_MAX/2+1))
9 #define HASZERO(x) ((x)-ONES & ~(x) & HIGHS)
10
strlcpy(char * d,const char * s,size_t n)11 size_t strlcpy(char *d, const char *s, size_t n)
12 {
13 char *d0 = d;
14 size_t *wd;
15
16 if (!n--) goto finish;
17 #ifdef __GNUC__
18 typedef size_t __attribute__((__may_alias__)) word;
19 const word *ws;
20 if (((uintptr_t)s & ALIGN) == ((uintptr_t)d & ALIGN)) {
21 for (; ((uintptr_t)s & ALIGN) && n && (*d=*s); n--, s++, d++);
22 if (n && *s) {
23 wd=(void *)d; ws=(const void *)s;
24 for (; n>=sizeof(size_t) && !HASZERO(*ws);
25 n-=sizeof(size_t), ws++, wd++) *wd = *ws;
26 d=(void *)wd; s=(const void *)ws;
27 }
28 }
29 #endif
30 for (; n && (*d=*s); n--, s++, d++);
31 *d = 0;
32 finish:
33 return d-d0 + strlen(s);
34 }
35